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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Indole 3-dimethylsulfonium ylids : a study of their chemical and physical properties

Park, Kyong-Hwi 04 1900 (has links) (PDF)
Ph.D. / Organic Chemistry / Synthesis of sulfonium ylids, 3-dimethylsulfonioindolide, 3-dimethylsulfonio- 2-methylindolide and 3-dimethylsulfonio-2-phenylindolide were accomplished. Carbon-13.and [superscript 1] H nmr of ylids and the related thioethers and sulfonium salts were studied in an attempt to describe the electronic changes occurring within the indole system to accommodate ylid stabilization. In a study of their physical properties, it was discovered that the sulfonium salt <===> ylid system displayed a hysteresis during acid - base titration. The cause for the hysteresis was shown to be a result of covalent hydration (probably of the indole C2-C3 double bond). The uv spectra of the ylid and its analogs differed in aqueous and nonaqueous solvents suggesting that a chemical reaction occurred in protic solution. The [superscript 1] H nmr of sulfonium salts in protic solvents revealed the formation of a new species in the solution. This new species, upon acid - base titration exhibited a titration hysteresis identical to that previously observed in titration of either sulfonium salt or ylid. The mass spectra of the sulfonium salts and ylids by different techniques (EI, EI with rapid sample heating and FD) were obtained; by the newly developed technique of electron ionization with rapid heating and photoplate ion recording, indole sulfonium salt "hydrates" exhibit ions assignable as sulfonium salt hydrate species.
2

Oxidation and reduction studies of polyphenylene suldide and its model compounds

Hsu, Songman 12 1900 (has links)
No description available.

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